Clinical studies and practice have shown that providing a reduced pressure in proximity to a tissue site augments and accelerates the growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but application of reduced pressure has been particularly successful in treating wounds. This treatment (frequently referred to in the medical community as “negative pressure wound therapy,” “reduced pressure therapy,” or “vacuum therapy”) provides a number of benefits, including faster healing and increased formulation of granulation tissue. Typically, reduced pressure is applied to tissue through a porous pad or other manifold device. The porous pad contains cells or pores that are capable of distributing reduced pressure to the tissue and channeling fluids that are drawn from the tissue. The porous pad often is incorporated into a dressing having other components that facilitate treatment.
Wound fluids or exudates are generally collected in a canister for disposal or analysis. Wound fluid primarily comprises plasma in addition to red and white blood cells, platelets, bacteria, and a variety of proteinaceous material. Plasma consists primarily of saline. In clinical practice, canisters should be sized appropriately to obviate the need for frequent replacement even when used in the treatment of patients with wounds generating a high volume of exudate. Conversely, canisters should not be bulky so as to fill care facilities' storage spaces or consume unnecessary resources for hazardous waste disposal of canisters filled with potentially infectious bodily fluid.